This invention relates to devices for storing and subsequently mixing of materials, but more particularly to devices which can be reused depending upon the chemical nature of the materials. U.S. Pat. Nos. 3,241,722 to Nissen and 3,454,198 and 3,508,685 to Flynn teach a dispensing device for two materials stored in two containers but make no mention of a collapsible second container necessary to dispense contents while only one material is under pressue. U.S. Pat. No. 3,896,971 to Schwede teaches a dispensing device for two materials stored in two containers, disclosing that one container would have to be collapsible. However, the two containers are not permanently affixed; that is, container 1 would have to be attached to the nozzle of container 2 to be used and removed when not in use. The valve assembly mentions no means of internal mixing of the materials, plus utilization requires the pressing by hand of both the second bag and the nozzle being that the second bag is externally mounted. These inventions can be used to dispense whipped cream traced with color and/or flavoring but does not afford total mixing of components in the present invention.